Chemical and Biological Studies of Endophytes Isolated from Marchantia polymorpha

Antibacterial, Antifungal, and Cytotoxic Effects of Endophytic Streptomyces Species Isolated from the Himalayan Regions of Nepal and Their Metabolite Study

Background/Objectives: Recently, antimicrobial-resistant pathogens and cancers have emerged as serious global health problems, highlighting the immediate need for novel therapeutics. Consequently, we aimed to isolate and characterize endophytic Streptomyces strains from the rhizospheres of the Himalayan region of Nepal and identify specialized metabolites with antibacterial, antifungal, and cytotoxic potential. Methods: To isolate Streptomyces sp., we collected two soil samples and cultured them on an ISP4 medium after pretreatment. We isolated and identified the strains PY108 and PY109 using a combination of morphological observations and 16S rRNA gene sequencing. Results: The BLAST results showed that PY108 and PY109 resembled Streptomyces hundungensis PSB170 and Streptomyces sp. Ed-065 with 99.28% and 99.36% nucleotide similarity, respectively. Antibacterial assays of ethyl acetate (EA) extracts from both isolates PY108 and PY109 in a tryptic soy broth (TSB) medium were conducted against four pathogenic bacteria. They showed significant antibacterial potential against Staphylococcus aureus and Klebsiella pneumoniae. Similarly, these extracts exhibited moderate antifungal activities against Saccharomyces cerevisiae and Aspergillus niger. Cytotoxicity assays on cervical cancer cells (HeLa) and breast cancer cells (MCF-7) revealed significant potential for both extracts. LC-MS/MS profiling of the EA extracts identified 27 specialized metabolites, including diketopiperazine derivatives, aureolic acid derivatives such as chromomycin A, and lipopeptide derivatives. In comparison, GC-MS analysis detected 34 metabolites, including actinomycin D and γ-sitosterol. Furthermore, a global natural product social molecular networking (GNPS)-based molecular networking analysis dereplicated 24 metabolites in both extracts. Conclusions: These findings underscore the potential of endophytic Streptomyces sp. PY108 and PY109 to develop new therapeutics in the future.

Analysis of Marchantia polymorpha-microorganism interactions: basis for understanding plant-microbe and plant-pathogen interactions

Marchantia polymorpha is a bryophyte gaining significance as a model plant in evolutionary studies in recent years. This is attributed to its small-sequenced genome, standardized transformation methodology, global distribution, and easy and rapid in vitro culturing. As an evolutionary model, M. polymorpha contributes to our understanding of the evolution of plant defensive responses and the associated hormonal signaling pathways. Through its interaction with microorganisms, M. polymorpha serves as a valuable source of knowledge, yielding insights into new microbial species and bioactive compounds. Bibliographic analysis involved collecting, reading, and categorizing documents obtained from the Scopus and Web of Science databases using different search terms. The review was based on 30 articles published between 1995 and 2023, with Japanese and Spanish authors emerging as the most prolific contributors in this field. These articles have been grouped into four main themes: antimicrobial metabolites produced by M. polymorpha; identification and characterization of epiphytic, endophytic, and pathogenic microorganisms; molecular studies of the direct interaction between M. polymorpha and microorganisms; and plant transformation using bacterial vectors. This review highlights the key findings from these articles and identifies potential future research directions.

Optimization of Fermentation Process for New Anti-Inflammatory Glycosylceramide Metabolite from Aspergillus sp

A novel ceramide compound, named Aspercerebroside A (AcA), was successfully isolated from the ethyl acetate layer of the marine symbiotic fungus Aspergillus sp. AcA exhibited notable anti-inflammatory activity by effectively inhibiting the production of nitric oxide (NO) in RAW 264.7 cells at concentrations of 30 μg/mL and 40 μg/mL, offering a promising avenue for the treatment of inflammatory diseases. To optimize the yield of glycosylceramide (AcA), a series of techniques, including single-factor experiments, orthogonal experiments, and response surface optimization, were systematically employed to fine-tune the composition of the fermentation medium. Initially, the optimal carbon source (sucrose), nitrogen source (yeast extract powder), and the most suitable medium salinity (14 ppt) were identified through single-factor experiments. Subsequently, orthogonal experiments, employing an orthogonal table for planning and analyzing multifactor experiments, were conducted. Finally, a mathematical model, established using a Box-Behnken design, comprehensively analyzed the interactions between the various factors to determine the optimal composition of the fermentation medium. According to the model's prediction, when the sucrose concentration was set at 37.47 g/L, yeast extract powder concentration at 19.66 g/L, and medium salinity at 13.31 ppt, the predicted concentration of glycosylceramide was 171.084 μg/mL. The experimental results confirmed the model's accuracy, with the actual average concentration of glycosylceramide under these conditions measured at 171.670 μg/mL, aligning closely with the predicted value.

UHPLC-QTOF-MS Metabolic Profiling of Marchantia polymorpha and Evaluation of Its Hepatoprotective Activity Using Paracetamol-Induced Liver Injury in Mice

Marchantia species were traditionally used to treat liver failure. Marchantia polymorpha chloroform extract showed a marked hepatoprotective activity in a dose-dependent manner in paracetamol-induced extensive liver damage in mice. At a dose of 500 mg/kg (MP-500), it resulted in a reduction in aspartate transaminase by 49.44%, alanine transaminase by 44.11%, and alkaline phosphatase by 24.4% with significant elevation in total proteins by 58.69% with respect to the diseased group. It showed significant reductions in total bilirubin, total cholesterol, triglycerides, low density lipoprotein (LDL), very LDL, total lipids, and to high density lipoprotein ratio (CH/HDL) by 53.42, 30.14, 35.02, 45.79, 34.74, 41.45, and 49.52%, respectively, together with a 37.69% increase in HDL with respect to the diseased group. It also showed an elevation of superoxide dismutase by 28.09% and in glutathione peroxidase by 81.83% in addition to the reduction of lipid peroxidation by 17.95% as compared to the paracetamol only treated group. This was further supported by histopathological examination that showed normal liver architecture and a normal sinusoidal gap. Metabolic profiling by ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometer (UHPLC-QTOF/MS) led to the tentative identification of 28 compounds belonging to phenols, quinolones, phenylpropanoid, acylaminosugars, terpenoids, lipids, and fatty acids to which the activity was attributed. Four compounds were detected in the negative ionization mode which are neoacrimarine J, marchantin A, chitobiose, and phellodensin F, while the rest were detected in the positive mode. Thus, it can be concluded that this plant could serve as a valuable choice for the treatment of hepatotoxicity that further consolidated its traditional use.

Bioactive Compounds Produced by Endophytic Microorganisms Associated with Bryophytes—The “Bryendophytes”

The mutualistic coexistence between the host and endophyte is diverse and complex, including host growth regulation, the exchange of substances like nutrients or biostimulants, and protection from microbial or herbivore attack. The latter is commonly associated with the production by endophytes of bioactive natural products, which also possess multiple activities, including antibacterial, insecticidal, antioxidant, antitumor, and antidiabetic properties, making them interesting and valuable model substances for future development into drugs. The endophytes of higher plants have been extensively studied, but there is a dearth of information on the biodiversity of endophytic microorganisms associated with bryophytes and, more importantly, their bioactive metabolites. For the first time, we name bryophyte endophytes “bryendophytes” to elaborate on this important and productive source of biota. In this review, we summarize the current knowledge on the diversity of compounds produced by endophytes, emphasizing bioactive molecules from bryendophytes. Moreover, the isolation methods and biodiversity of bryendophytes from mosses, liverworts, and hornworts are described.